Process of manufacturing rubber thread and the like



Patented Apr. 16, 1940 I 2,197,088 "PRooEss'oF MANUFACTURING RUBBER T EAD AND THE LIKE I T'HarryLoguc'Welker and Frits Cremer, Williams- =,";,port, Pa., assignors to Harry liogue Welker,

Williamsport, Pa.-

No Drawing. Application January 5, 1937, Serial No. 119,159

4 Claims.

This invention relates to rubber threads and sheets of rubber manufactured in the form of tubes, reticulated networks of rubber tubing or superposed layers of rubber separated by a disintegrated core, and also to the process of manufacturing such threads or sheets. I

The main object of the invention is to produce an article of the character described which may be of any desired cross-sectional dimension and have all the advantages and characteristics inherent in articles of this type manufactured in tubular form.

A further object of the invention resides in the method designed to efiect the manufacture of the articles referred to. r

Other-objects of the invention will become apparent as the detailed description thereof proceeds.

In general, the method involved in manufacturing the aforesaid articles consists indepositing a solution or dispersion of rubber or similar elastic material upon a filament or upon a web of material constituting a temporary support, and then subjecting the coated material to a bath of coagulant which not only serves to coagulate the material upon the filament or web, but also serves to reduce to ash the filament or web forming the core for the article thus treated.

The process of manufacturing may be car ried out on any apparatus such as is commonly used in this art for depositing rubber latex or The in-.

rubber in solution upon a textile core. vention is not particularly concerned with the apparatus, which may be of the general type illustrated in the patent to Harrison No. 2,030,208, dated February 11, 1936.

In carrying out this process, any number of filaments or cords or webs of textile material, such as loosely twisted short cotton fabrics or untwisted cellulose, are drawn through a bath of rubber latex or similar material. The coated core thus formed is then drawn through a bath of coagulant which not only coagulates the deposit, but also operates through the rubber deposit to reduce the core to ash.

The time necessary to effect complete reduction to ash of the core depends upon the concentrationof the coagulant used. Several acid coagulants are available for the purpose of coagulating the latex deposit upon its support and for reducing the support to ash after the formation thereon of the coating. However, we have found that sulphuric acid and alcohol combine latex coating and to reduce the core to ash after formation of the coating. A coagulant including equal parts of alcohol gives satisfactory results, although the coagulation and core reduction can be effected with a coagulant comprising one part 5 sulphuric acid to five parts of alcohol. The speed of reduction of the core to ash varies with the proportion of sulphuric acid employed. The best results, however, are obtained by using a coagulant having two parts of sulphuric acid to one 0 part of alcohol.

Sulphuric acid used alone. is a very good agent for destroying the core, and works much more rapidly than any combination with other ingredients. Furthermore, the quality of the rubber product is notimpaired by the use of this acid as a core reducing agent. Hydrochloric acid destroys the textile core very effectively, but it has a noticeable effect on the product; that is, the

elasticity of the latex is not quite as good as in 20 Nitric, acid will also perform the core reducing f function; but like hydrochloric acid, it seems to leave the product tougher but less elastic.

Substantially the same result can be obtained by incorporating sulphuric acid as a core reducing agent in the latex. This can be done very well so long as the pH or the alkalinity of the latex is kept high. After coating with the treated latex, the article is removed from the bath and I dried, then washed and vulcanized in the usual manner. In another method, two or more materials'added to latex react, with increase of temperature, to produce a coagulating agent. For 85 example, ammonium persulphate and trioxy- *methylene have been used for this purpose, the

coagulating action probably resulting from the ultimate formation of sulphuric acid. 1

It is to be understood that the textile material employed in this process must be capable of being reduced to ash by the coagulant employed for that purpose. Obviously, the reducing of the 1 core to ash coupled with the tension exerted on the threads indrawing them through the coagulant causes a collapse or shrinkage of the threads which compress the ashes of the core which then become imbedded in the substantially solid re-' sultant elastic material. .The invention is not concerned with processes which do not permit shrinkage of the rubber during vulcanization.

What we claim is:

l. A method of making an ,elastic thread which comprises providing a cellulosic textile fibre, forming a coating of rubber latex upon the fibre, applying sulphuric acid. to disintegrate the fibre and to coagulate the unvulcanized coating,'and after disintegration of the fibre vulcanizing the coating.

2. A method of making an elastic thread which comprises providing a cellulosic textile fibre, forming a coating of rubber latex upon the fibre,

applying acid from the group consisting of sulphuric acid, hydrochloric acid and nitric acid .to disintegrate the fibre and to coagulate the unvulcanized coating, and after disintegration of the fibre vulcanizing the coating.

3. A method of making an elastic thread which comprises providing a cellulosic textile fibre,

forming a coating of rubber latex upon-the fibre, applying a solution of about 16 to 33% sulphuric acid to disintegrate theiibre and to coagulate c the unvulcanized coating, and after disintegration of the fibre vulcanizing the coating.

4. A method of making an elastic thread which comprises providing a cellulosictextile fibre,

rormi'ng'a coating of rubber latex upon the fibre,

applying a solution of alcohol containing about 16 to about 33% sulphuric acid to disintegrate the fibre and to coagulate the unvulcanized coating, and after disintegration the coating. I v v HARRY LOGUE WELKER. l FRITS CREME-R.

of the fibre vulcanizing' 

